Vaccine against varicella-zoster virus

ABSTRACT

A gene of varicella-zoster virus (VZV) which encodes immunogenic outer surface viral proteins has been identified by DNA sequence analysis. Antibodies directed against peptides imputed from the DNA sequence can react with the glycoprotein, which itself is reactive with neutralizing antibodies. The amino-terminal sequence of the purified glycoprotein is identical to a portion of the amino acid sequence imputed from the DNA sequence. This glycoprotein is useful for the preparation of a vaccine against VZV.

BACKGROUND OF THE INVENTION

Chickenpox is caused by varicella-zoster virus (VZV), a member of the herpesvirus group. The disease occurs in persons with no prior VZV immunity VZV-specific antibodies can be demonstrated shortly after onset of disease, decline during convalescence, but remain detectable for many years and correlate with immunity to the disease. Chickenpox is highly contagious; over 90% of the population becomes exposed to VZV before they are 20 years old. In most, if not all cases, VZV apparently becomes latent in dorsal root ganglion cells. From this latent state, VZV can reactivate and cause zoster even in the presence of specific antibodies, probably as a result of weakened cellular immunity. The disease is highly morbid to the immunosuppressed and to those beyond the second decade.

VZV has five major glycoproteins on its surface: gp115 [115 kilodalton (kD) glycoprotein], gp105, gp92, gp83, gp55. These glycoproteins apparently are the products of three genes: gpIII (gp105), gpII (gp115, in the nonreduced state, composed of the reduced species gp62 and gp57), and gpI (gp92, gp83, gp55). Formerly, these genes were referred to as gA, gB, and gC, respectively. Monoclonal (McAb) and polyclonal monospecific antibodies to gA and gB display complement-independent neutralization, and such antibodies to gC display complement-dependent neutralization of VZV.

SUMMARY OF THE INVENTION

A gene of VZV which encodes the immunogenic outer surface viral glycoprotein gpIII has been identified by DNA sequence analysis. Antibodies directed against peptides imputed from the DNA sequence can react with the gpIII glycoprotein which itself is the target of neutralizing antibodies. The amino-terminal sequence of purified gpIII is identical to a portion of the amino acid sequence imputed from the DNA sequence. This glycoprotein is useful for the preparation of a vaccine for VZV.

OBJECTS OF THE INVENTION

It is an object of the present invention to provide antigens which will prevent diseases associated with VZV infections. Another object is to provide antigens which can be used diagnostically to detect antibodies to VZV. Another object is to provide methods for the preparation of these antigens. Another object is to provide methods for using the antigens to raise antibodies to VZV. Another object is to describe the full sequence of protein antigens, which will include peptide antigens, which may be synthesized by other means or expressed in expression vectors. These and other objects of the present invention will be apparent from the following description.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to the identification of that VZV DNA segment which encodes the protective immunogenic gpIII glycoprotein. More specifically, it is directed to a 2.5 kilobase pair (kbp) DNA fragment whose respective nucleotide sequence (and derived amino acid sequence) has been located within the known sequence of the entire VZV genome. The present invention also is directed to vectors containing all or part of this 2.5 kbp DNA fragment. The invention also is directed to host cells which contain these vectors and which cells are capable of expressing all or part of the polypeptide encoded by the 2.5 kbp fragment. In accordance with known techniques, it will be obvious to those skilled in the art that parts of the foregoing polypeptide can be synthesized chemically or modified and still retain immunogenicity. Therefore, the present invention also is directed toward chemical synthesis of domains of this protein, especially domains including and surrounding hydrophilic regions and threonine or serine and asparagine-X-serine or asparagine-X-threonine residues, wherein X is any amino acid residue, since these domains are likely to reside on the outer surface of the virus.

The DNA segment which encodes gpIII is identified precisely as follows: By use of immuneaffinity chromatography mediated by McAb to VZV gpIII, the gpIII polypeptide is purified to 90% homogeneity. This preparation, when inoculated into guinea pigs in complete Freund's adjuvant, is capable of eliciting the production of neutralizing antibodies. This purified preparation is electrophoresed by preparative sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE) and isolated on polybrene-coated glass-fiber sheets as a single 105 kD polypeptide. This sample is subjected to amino-terminal sequence analysis. Based upon a run of 7 consecutive amino acids resolved in the analysis, a pool of oligonulceotides fragment every possible coding combination for the heptapeptide is synthesized. The oligonucleotide pool is radiolabelled for use as a hybridization probe to VZV DNA fragments. Specific hybridization is found to a domain within the HindIII B fragment. DNA sequence analysis of this region of HindIII B reveals a 2.5 kbp open reading frame (ORF). Within the amino acid sequence imputed from this DNA sequence, residues 18-27 form a perfect match with the amino-terminal sequence described above. Based on the imputed amino acid sequence, 3 peptides of lengths 13-22 residues are selected as likely to be immunogenic. These peptides are synthesized, coupled to bovine serum albumin, and injected into rabbits. Some of the anti-peptide sera are reactive with gpIII by Western blot analysis and by immunoprecipitation analysis. Further specificity of the anti-peptide serum is shown by the ability of anti-peptide antibodies to compete with McAb to gpIII in immunoprecipitation analysis. In addition, the anti-peptide antibodies can immunoprecipitate an 80 kD in vitro translational product of mRNA hybrid selected by the 2.5 kbp ORF.

In accordance with known techniques, it will be obvious to those skilled in the art that all or part of the above-mentioned DNA fragment can be placed into an expression vector system in order to produce all or part of the protective immunogenic polypeptide. Such an expression vector system often consists of a plasmid which is inserted into a prokaryotic or eukaryotic cell in order to direct expression of a foreign polypeptide. Such a plasmid usually contains sequences for selection of host cells containing the plasmid, amplification of plasmid copy number within the host cell, initiation of transcription of the gene for the foreign polypeptide, termination of transcription of the gene for the foreign polypeptide, in addition to the coding sequence per se which specifies the foreign polypeptide. Therefore, the present invention also is directed to host cells and vectors containing all or part of the 2.5 kbp DNA fragment. Examples of suitable host cells for expression of VZV proteins include prokaryotic cells, such as E. coli and B. subtillis, and eukaryotic cells, such as S. cerevisiae and continuous mammalian cell lines including but not limited to Chinese Hamster Ovary cells and Vero cells.

These proteins are useful individually or in combination when placed in a physiologically acceptable carrier, e.g., saline or phosphate buffered saline, to elicit neutralizing antibodies against VZV disease when administered to a member of a mammalian species, e.g., quinea pigs, in an amount of approximately 5 to 150 mcg per dose, preferably from approximately 10 to 50 mcg per dose. One or more doses may be administered to produce effective protection against VZV disease. The protein may be administered by injection, e.g., subcutaneously or intramuscularly. It is also to be understood that these proteins can be expressed directly in humans by means of appropriate viral expression vectors such as adeno, vaccinia, or herpes simplex.

The following examples illustrate the present invention without, however, limiting the same thereto. The disclosure of each reference mentioned in the following examples is hereby incorporated by reference.

EXAMPLE I Purification of VZV gpIII Glycoprotein

Ascites fluids carrying McAb Al (described in Keller et al., J. Virology 52: 293, 1984), were harvested from mice. An equal volume of 0.15 M NaCl was added. Then, a saturated (NH₄)₂ SO₄ solution was added in an equal total volume and held at 4° C. overnight. This mixture was centrifuged at 10° C. and 2000 rpm. The pellet was resuspended in distilled H₂ O (2 mg/ml) and dialyzed overnight against coupling buffer (0.1M NaHCO₃, 0.5 M NaCl, pH 8.4). One gram of cyanogen bromide-activated Sepharose 4B (Pharmacia, Piscataway, N.J.) was swollen in 0.001N HCl, then decanted into a 60 ml coarse sintered glass funnel. This was washed with 200 ml 0.002N HCl, then 50 ml coupling buffer. The Sepharose then was mixed with 10 ml of McAb solution and rotated for 2 hours at 23° C. Then, 80 μl ethanolamine was added and the solution was rotated for 1 hour at 23° C. The resin was poured into a disposable chromatography column (BioRad), drained and washed successively with 10 ml volumes of the following solutions: (1) coupling buffer; (2) 0.lM Na₂ HPO₄ ; 0.5M NaCl, pH 8.2;(3) 0.1M NaOAc, 0.5M NaCl, pH 4.0;(4) 0.1M NaHBO₄, pH 8.2;(5) 3M KSCN; (6) 0.1M NaHBO₄, pH 8.2. Then it is stored in 0.lM NaHBO₄, pH 8.2 at 4° C. prior to use.

VZV glycoproteins were purified form MRC-5 human diploid fibroblasts which were infected with VZV to the extent of 80% cytopathic effect. Cells in 750 cm² roller bottles were washed twice with 0.15M NaCl, 0.01M Na₂ HPO₄, pH 7.2 and drained well. Ten ml of 50 mM Tris, pH 7.5, 2% Triton X-100, 4 mM phenylmethylsulfonylfluoride (PMSF) were incubated 15 minutes to the bottle while rolling. The same 10 ml then were used successively to extract 9 more roller bottles. A fresh 10 ml aliquot of buffer was used successively to rinse the 10 roller bottles and pooled with the first aliquot, such that 20 ml of extract represent material from 10 roller bottles. Extracts were stored at -70° C. until use. Extracts were thawed and dialyzed overnight at 4° C. against 0.15M NaCl, 0.01M Na₂ HPO₄, 0.05% Triton X-100, PH 7.2, then clarified by centrifuging at 1500 rpm for 15 minutes at 4° C. Extract (20 ml) was added to 1 g of McAb-coupled resin and incubated overnight at 4° C. with shaking. The slurry was centrifuged for 15 minutes at 1500 rpm at 4° C. and washed three times with 0.1M NaHBO₄, pH 8.2. The glycoprotein was eluted by incubation at 23° C. with 10 ml 3M KSCN. The eluate immediately was dialyzed against 0.15M NaCl, 0.01M Na₂ HPO₄, 0.05% Triton X-100, pH 7.2 overnight at 4° C. and concentrated to approximately 1 mg/ml.

This peak was verified as VZV gpIII by the following criteria. In silver stains of SDS-PAGE run under reducing conditions, the sample was resolved as one polypeptide species of molecular weight 105 kD as described in Keller et al., ibid., i.e., gp105; Shiraki et al., J. Gen. Virology 61: 255 (1982), i.e., gpl; Grose et al., Inf. Immun. 40: 381 (1983), i.e., gp118, Forghani et al., J. VirologY 52: 55 (1984), i.e., 118K. In addition, a parallel aliquot of [³⁵ S]-methioninelabelled cell extract purified by the technique could be immunoprecipitated specifically with McAb to gpIII, resulting in the resolution by SDS-PAGE of a single 105 kD species.

EXAMPLE II Purified VZV gpIII polypeptide induces antibodies which neutralize VZV infectivity in vitro

Guinea pigs were inoculated intramuscularly with 20 micrograms in complete Freund's adjuvant of VZV gpIII (purified by immune-affinity chromatography as described above in Example I), followed one month later by two inoculations each of ten micrograms of VZV gpIII in incomplete Freund's adjuvant spaced two weeks apart. Sera were obtained from the guinea pigs after these three inoculations. Each of the guinea pig sera were utilized in an in vitro VZV neutralization assay as described (Keller et al., ibid.). By this assay, the post-immunization, but not the pre-immunization sera, contained VZV-neutralizing antibodies.

EXAMPLE III N-Terminal amino acid sequence of purified VZV gpIII polypeptide

200 μg of VZV gpIII, prepared as described in Example I, were electrophoresed by preparative SDS-PAGE (7.5% polyacrylamide) and isolated on polybrene-coated glass-fiber sheets as a single polypeptide of 105 kD [van de Kerckhove et al., Eur. J. Biochem. 152: 9 (1985)]. This sample was subjected to amino-terminal sequence analysis using an Applied Biosystems Gas-Phase Sequenator [Hewick et al., J. Biol. Chem. 256: 7790 (1981)]. The phenylthiohydantoin amino acids produced at each step were separated and quantitated by high performance liquid chromatography [Speiss et al., Proc. Nat. Acad. Sci. U.S.A. 70: 2974 (1979)]. The sequence analysis demonstrated that gpIII contains a single unblocked amino-terminus. As shown in Table I, this sequence (with 2 gaps) can be aligned perfectly with amino acids 18-27 in Example V (see below) which have been imputed from the DNA sequence of the 2.5 kbp ORF.

                  TABLE 1                                                          ______________________________________                                         N-Terminal amino acid sequence of purified VZV gpIII                           ______________________________________                                         1     asn    lys    ser tyr val  thr  pro  thr pro  ala                        2     18     19     20  21  22   23   24   25  26   27                         3     --     lys    ser tyr val  thr  pro  thr --   ala                        ______________________________________                                          1 = imputed amino acids from Example V.                                        2 = amino acid position in the ORF of sequence 1.                              3 = amino acid sequence of purified VZV gpIII, wherein a dash (--) means       that no amino acid was resolved at that position in the analysis.        

EXAMPLE IV Use of oligonucleotides based on amino acid sequence data to identify the gpIII gene

Based on the N-terminal amino acid sequence of gpIII, derived as described in Example III and presented in Table 1, a pool of oligonucleotides was designed which represents every possible combination of DNA sequences capable of encoding this amino acid sequence. This pool is ##STR1##

These oligonucleotide pools were labelled with [³² P] ATP in the presence of T4 polynucleotide kinase. The probe was hybridized to a Southern blot of HindIII fragments of VZV. By this analysis, the above gene sequence was localized to the HindIII B fragment.

EXAMPLE V Determination of nucleotide sequences of the 2.5 kbp seqment of VZV DNA

The complete nucleotide sequence of the VZV HindIII-B DNA segment contains several large ORFs. One of these ORFs is 2.5 kbp in length, encodes a 90 kD protein, and contains a DNA sequence (Example IV) which codes for the amino terminal gpIII sequence in Example III. The nucleotide sequence for the complete 2.5 kbp segment which encodes the gpIII glycoprotein is given below:

    __________________________________________________________________________     ATG TTT GCG CTA GTT TTA GCG GTG GTA ATT CTT CCT CTT TGG ACC ACG GCT AAT        AAA TCT TAC                                                                    GTA ACA CCA ACC CCT GCG ACT CGC TCT ATC GGA CAT ATG TCT GCT CIT CTA CGA        GAA TAT TCC                                                                    GAC CGT AAT ATG TCT CTG AAA TTA GAA GCC TTT TAT CCT ACT GGT TTC GAT GAA        GAA CTC ATT                                                                    AAA TCA CTT CAC TGG GGA AAT GAT AGA AAA CAC GTT TTC TTG GTT ATT GTT AAG        GTT AAC CCT                                                                    ACA ACA CAC GAA GGA GAC GTC GGG CTG GTT ATA TTT CCA AAA TAC TTG TTA TCG        CCA TAC CAT                                                                    TTC AAA GCA GAA CAT CGA GCA CCG TTT CCT GCT GGA CGT TTT GGA TTT CTT AGT        CAC CCT GTG                                                                    ACA CCC GAC GTG AGC TTC TTT GAC AGT TCG TTT GCG CCG TAT TTA ACT ACG CAA        CAT CTT GTT                                                                    GCG TTT ACT ACG TTC CCA CCA AAC CCC CTT GTA TGG CAT TTG GAA AGA GCT GAG        ACC GCA GCA                                                                    ACT GCA GAA AGG CCG TTT GGG GTA AGT CTT TTA CCC GCT CGC CCA ACA GTC CCC        AAG AAT ACT                                                                    ATT CTG GAA CAT AAA GCG CAT TTT GCT ACA TGG GAT GCC CTT GCC CGA CAT ACT        TTT TTT TCT                                                                    GCC GAA GCA ATT ATC ACC AAC TCA ACG TTG AGA ATA CAC GTT CCC CTT TTT GGG        TCG GTA TGG                                                                    CCA ATT CGA TAC TGG GCC ACC GGT TCG GTG CTT CTC ACA AGC GAC TCG GGT CGT        GTG GAA GTA                                                                    AAT ATT GGT GTA GGA TTT ATG AGC TCG CTC ATT TCT TTA TCC TCT GGA CCA CCG        ATA GAA TTA                                                                    ATT GTT GTA CCA CAT ACA GTA AAA CTG AAC GCG GTT ACA AGC GAC ACC ACA TGG        TTC CAG CTA                                                                    AAT CCA CCG GGT CCG GAT CCG GGG CCA TCT TAT CGA GTT TAT TTA CTT GGA CGT        GGG TTG GAT                                                                    ATG AAT TTT TCA AAG CAT GCT ACG GTC GAT ATA TGC GCA TAT CCC GAA GAG AGT        TTG GAT TAC                                                                    CGC TAT CAT TTA TCC ATG GCC CAC ACG GAG GCT CTG CGG ATG ACA ACG AAG GCG        GAT CAA CAT                                                                    GAC ATA AAC GAG GAA AGC TAT TAC CAT ATC GCC GCA AGA ATA GCC ACA TCA ATT        TTT GCG TTG                                                                    TCG GAA ATG GGC CGT ACC ACA GAA TAT TTT CTG TTA GAT GAG ATC GTA GAT GTT        CAG TAT CAA                                                                    TTA AAA TTC CTT AAT TAC ATT TTA ATG CGG ATA GGA GCA GGA GCT CAT CCC AAC        ACT ATA TCC                                                                    GGA ACC TCG GAT CTG ATC TTT GCC GAT CCA TCG CAG CTT CAT GAC GAA CTT TCA        CTT CTT TTT                                                                    GGT CAG GTA AAA CCC GCA AAT GTC GAT TAT TTT ATT TCA TAT GAT GAA GCC CGT        GAT CAA CTA                                                                    AAG ACC GCA TAC GCG CTT TCC CGT GGT CAA GAC CAT GTG AAT GCA CTT TCT CTC        GCC AGG CGT                                                                    GTT ATA ATG AGC ATA TAC AAG GGG CTG CTT GTG AAG CAA AAT TTA AAT GCT ACA        GAG AGG CAG                                                                    GCT TTA TTT TTT GCC TCA ATG ATT TTA TTA AAT TTC CGC GAA GGA CTA GAA AAT        TCA TCT CGG                                                                    GTA TTA GAC GGT CGC ACA ACT TTG CTT TTA ATG ACA TCC ATG TGT ACG GCA GCT        CAC GCC ACG                                                                    CAA GCA GCA CTT AAC ATA CAA GAA GGC CTG GCA TAC TTA AAT CCT TCA AAA CAC        ATG TTT ACA                                                                    ATA CCA AAC GTA TAC AGT CCT TGT ATG GGT TCC CTT CGT ACA GAC CTC ACG GAA        GAG ATT CAT                                                                    GTT ATG AAT CTC CTG TCG GCA ATA CCA ACA CGC CCA GGA CTT AAC GAG GTA TTG        CAT ACC CAA                                                                    CTA GAC GAA TCT GAA ATA TTC GAC GCG GCA TTT AAA ACC ATG ATG ATT TTT ACC        ACA TGG ACT                                                                    GCC AAA GAT TTG CAT ATA CTC CAC ACC CAT GTA CCA GAA GTA TTT ACG TGT CAA        GAT GCA GCC                                                                    GCG CGT AAC GGA GAA TAT GTG CTC ATT CTT CCA GCT GTC CAG GGA CAC AGT TAT        GTG ATT ACA                                                                    CGA AAC AAA CCT CAA AGG GGT TTG GTA TAT TCC CTG GCA GAT GTG GAT GTA TAT        AAC CCC ATA                                                                    TCC GTT GTT TAT TTA AGC AGG GAT ACT TGC GTG TCT GAA CAT GGT GTC ATA GAG        ACG GTC GCA                                                                    CTG CCC CAT CCG GAC AAT TTA AAA GAA TGT TTG TAT TGC GGA AGT GTT TTT CTT        AGG TAT CTA                                                                    ACC ACG GGG GCG ATT ATG GAT ATA ATT ATT ATT GAC AGC AAA GAT ACA GAA CGA        CAA CTA GCC                                                                    GCT ATG GGA AAC TCC ACA ATT CCA CCC TTC AAT CCA GAC ATG CAC GGG GAT GAC        TCT AAG GCT                                                                    GTG TTG TTG TTT CCA AAC GGA ACT GTG GTA ACG CTT CTA GGA TTC GAA CGA CGA        CAA GCC                                                                        ATA CGA ATG TCG GGA CAA TAC CTT GGG GCC TCT TTA GGA GGG GCG TTT CTG GCG        GTA GTG GGG                                                                    TTT GGT ATT ATC GGA TGG ATG TTA TGT GGA AAT TCC CGC CTT CGA GAA TAT AAT        AAA ATA CCT                                                                    CTG ACA TAA                                                                    __________________________________________________________________________

The foregoing nucleotide sequences encode the following peptide:

    __________________________________________________________________________     10                    20                                                       Met Phe Ala Leu Val Leu Ala Val Val Ile                                                              Leu Pro Leu Trp Thr Thr Ala Asn Lys Ser                  30                    40                                                       Tyr Val Thr Pro Thr Pro Ala Thr Arg Ser                                                              Ile Gly His Met Ser Ala Leu Leu Arg Glu                  50                    60                                                       Tyr Ser Asp Arg Asn Met Ser Leu Lys Leu                                                              Glu Ala Phe Tyr Pro Thr Gly Phe Asp Glu                  70                    80                                                       Glu Leu Ile Lys Ser Leu His Trp Gly Asn                                                              Asp Arg Lys His Val Phe Leu Val Ile Val                  90                    100                                                      Lys Val Asn Pro Thr Thr His Glu Gly Asp                                                              Val Gly Leu Val Ile Phe Pro Lys Tyr Leu                  110                   120                                                      Leu Ser Pro Tyr His Phe Lys Ala Glu His                                                              Arg Ala Pro Phe Pro Ala Gly Arg Phe Gly                  130                   140                                                      Phe Leu Ser His Pro Val Thr Pro Asp Val                                                              Ser Phe Phe Asp Ser Ser Phe Ala Pro Tyr                  150                   160                                                      Leu Thr Thr Gln His Leu Val Ala Phe Thr                                                              Thr Phe Pro Pro Asn Pro Leu Val Trp His                  170                   180                                                      Leu Glu Arg Ala Glu Thr Ala Ala Thr Ala                                                              Glu Arg Pro Phe Gly Val Ser Leu Leu Pro                  190                   200                                                      Ala Arg Pro Thr Val Pro Lys Asn Thr Ile                                                              Leu Glu His Lys Ala His Phe Ala Thr Trp                  210                   220                                                      Asp Ala Leu Ala Arg His Thr Phe Phe Ser                                                              Ala Glu Ala Ile Ile Thr Asn Ser Thr Leu                  230                   240                                                      Arg Ile His Val Pro Leu Phe Gly Ser Val                                                              Trp Pro Ile Arg Tyr Trp Ala Thr Gly Ser                  250                   260                                                      Val Leu Leu Thr Ser Asp Ser Gly Arg Val                                                              Glu Val Asn Ile Gly Val Gly Phe Met Ser                  270                   280                                                      Ser Leu Ile Ser Leu Ser Ser Gly Pro Pro                                                              Ile Glu Leu Ile Val Val Pro His Thr Val                  290                   300                                                      Lys Leu Asn Ala Val Thr Ser Asp Thr Thr                                                              Trp Phe Gln Leu Asn Pro Pro Gly Pro Asp                  310                   320                                                      Pro Gly Pro Ser Tyr Arg Val Tyr Leu Leu                                                              Gly Arg Gly Leu Asp Met Asn Phe Ser Lys                  330                   340                                                      His Ala Thr Val Asp Ile Cys Ala Tyr Pro                                                              Glu Glu Ser Leu Asp Tyr Arg Tyr His Leu                  350                   360                                                      Ser Met Ala His Thr Glu Ala Leu Arg Met                                                              Thr Thr Lys Ala Asp Gln His Asp Ile Asn                  370                   380                                                      Glu Glu Ser Tyr Tyr His Ile Ala Ala Arg                                                              Ile Ala Thr Ser Ile Phe Ala Leu Ser Glu                  390                   400                                                      Met Gly Arg Thr Thr Glu Tyr Phe Leu Leu                                                              Asp Glu Ile Val Asp Val Gln Tyr Gln Leu                  410                   420                                                      Lys Phe Leu Asn Tyr Ile Leu Met Arg Ile                                                              Gly Ala Gly Ala His Pro Asn Thr Ile Ser                  430                   440                                                      Gly Thr Ser Asp Leu Ile Phe Ala Asp Pro                                                              Ser Gln Leu His Asp Glu Leu Ser Leu Leu                  450                   460                                                      Phe Gly Gln Val Lys Pro Ala Asn Val Asp                                                              Tyr Phe Ile Ser Tyr Asp Glu Ala Arg Asp                  470                   480                                                      Gln Leu Lys Thr Ala Tyr Ala Leu Ser Arg                                                              Gly Gln Asp His Val Asn Ala Leu Ser Leu                  490                   500                                                      Ala Arg Arg Val Ile Met Ser Ile Tyr Lys                                                              Gly Leu Leu Val Lys Gln Asn Leu Asn Ala                  510                   520                                                      Thr Glu Arg Gln Ala Leu Phe Phe Ala Ser                                                              Met Ile Leu Leu Asn Phe Arg Glu Gly Leu                  530                   540                                                      Glu Asn Ser Ser Arg Val Leu Asp Gly Arg                                                              Thr Thr Leu Leu Leu Met Thr Ser Met Cys                  550                   560                                                      Thr Ala Ala His Ala Thr Gln Ala Ala Leu                                                              Asn Ile Gln Glu Gly Leu Ala Tyr Leu Asn                  570                   580                                                      Pro Ser Lys His Met Phe Thr Ile Pro Asn                                                              Val Tyr Ser Pro Cys Met Gly Ser Leu Arg                  590                   600                                                      Thr Asp Leu Thr Glu Glu Ile His Val Met                                                              Asn Leu Leu Ser Ala Ile Pro Thr Arg Pro                  610                   620                                                      Gly Leu Asn Glu Val Leu His Thr Gln Leu                                                              Asp Glu Ser Glu Ile Phe Asp Ala Ala Phe                  630                   640                                                      Lys Thr Met Met Ile Phe Thr Thr Trp Thr                                                              Ala Lys Asp Leu His Ile Leu His Thr His                  650                   660                                                      Val Pro Glu Val Phe Thr Cys Gln Asp Ala                                                              Ala Ala Arg Asn Gly Glu Tyr Val Leu Ile                  670                   680                                                      Leu Pro Ala Val Gln Gly His Ser Tyr Val                                                              Ile Thr Arg Asn Lys Pro Gln Arg Gly Leu                  690                   700                                                      Val Tyr Ser Leu Ala Asp Val Asp Val Tyr                                                              Asn Pro Ile Ser Val Val Tyr Leu Ser Arg                  710                   720                                                      Asp Thr Cys Val Ser Glu His Gly Val Ile                                                              Glu Thr Val Ala Leu Pro His Pro Asp Asn                  730                   740                                                      Leu Lys Glu Cys Leu Tyr Cys Gly Ser Val                                                              Phe Leu Arg Tyr Leu Thr Thr Gly Ala Ile                  750                   760                                                      Met Asp Ile Ile Ile Ile Asp Ser Lys Asp                                                              Thr Glu Arg Gln Leu Ala Ala Met Gly Asn                  770                   780                                                      Ser Thr Ile Pro Pro Phe Asn Pro Asp Met                                                              His Gly Asp Asp Ser Lys Ala Val Leu Leu                  790                   800                                                      Phe Pro Asn Gly Thr Val Val Thr Leu Leu                                                              Gly Phe Glu Arg Arg Gln Ala Ile Arg Met                  810                   820                                                      Ser Gly Gln Tyr Leu Gly Ala Ser Leu Gly                                                              Gly Ala Phe Leu Ala Val Val Gly Phe Gly                  830                   840                                                      Ile Ile Gly Trp Met Leu Cys Gly Asn Ser                                                              Arg Leu Arg Glu Tyr Asn Lys Ile Pro Leu                  850                   860                                                       Thr                                                                           __________________________________________________________________________

EXAMPLE VI

Based on the DNA sequence of Example V and its imputed amino acid sequence, 3 domains were chosen for the synthesis of peptides which would be likely to elicit the production of antibodies against gpIII. These domains are : (1) Phe¹⁵² -pro¹⁷³ (22-mer), (2) glu⁷⁹³ -tyr⁸⁰⁴ (12-mer), and (3) gly⁸²⁸ -thr⁸⁴¹ (14 mer). The first 2 were obtained from Peninsula Laboratories Inc. The latter was synthesized on an Applied Biosystems Inc. 430A solid-phase peptide synthesizer. All synthetic peptides, with an amino-terminal acetyl group and a carboxy-terminal hydroxyl group, were characterized by reversed-phase high performance liquid chromatography and amino acid analysis. Each peptide was conjugated to bovine serum albumin according to established techniques [Walter et al., Proc. Natl. Acad. Sci. USA 77:5197 (1980); Gutkowska et al., Biochem. Biophys. Res. Commun. 122:593 (1984)]. A quantity, 5-10 mg/1.0 ml, of each conjugate was injected into rabbits intramuscularly in complete Freund's adjuvant at week 0 and in incomplete Freund's adjuvant at week 4. Rabbits were bled at week 8. Sera were utilized in Western blot analysis at 1:500 dilutions. The antisera recognized a 105 kD polypeptide. In immunoprecipitation analyses, 1:30 dilutions of sera that were incubated with [³⁵ S] methionine-labelled infected cell extracts immunoprecipitated a 105 kD polypeptide. The 105 kD species was conclusively demonstrated to be gpIII by virtue of the ability of McAb to gpIII (Al in Keller et al., ibid.), but not McAb to gpI or gpII (C5 and B₁, respectively in Keller et al., ibid.), to preclear the 105 kD polypeptide from the lysate by 2 successive immunoprecipitations, as shown by abrogation of the immunoprecipitability of the 105 kD polypeptide by the anti-peptide sera.

EXAMPLE VII The 2.5 kbp DNA ORF can select RNA encodinc the precursor protein to gpIII

Cystoplasmic RNA was prepared from VZV-infected MRC-5 cells as described (Chirgwin et al., Biochemistry 18: 5294 (1979). The RNA encoded by the 2.5 kbp ORF in the VZV HindIII B fragment as well as nonselected RNA and RNA selected by other fragments were selected by hybridization to cloned VZV DNA fragments [Ecker & Hyman, Proc. Natl. Acad. Sci. USA 79:156 (1982)] bound to nitrocellulose [Cooper et al., J. Virology 37: 284 (1981)]. These RNAs were translated in a rabbit reticulocyte lysate. The polypeptide products were immunoprecipitated by one polyclonal monospecific rabbit antibody raised to the synthetic peptide described in Example VI. By this analysis, it was found that an 80 kD in vitro translational product from mRNA selected by the 2.5 kbp ORF in the VZV HindIII-B fragment could be immunoprecipitated by the anti-peptide sera. 

What is claimed is:
 1. An immunogenic subunit comprising one of amino acid sequences

    ______________________________________                                         Phe Pro Pro Asn Pro Leu Val Trp His Leu Glu Arg                                Ala Glu Thr Ala Ala Thr Ala Glu Arg Pro,                                       Glu Arg Arg Gln Ala Ile Arg Met Ser Gly Gln Tyr,                               or                                                                             Gly Asn Ser Arg Leu Arg Glu Tyr Asn Lys Ile Pro                                Leu Thr.                                                                       ______________________________________                                          . 